"Whoever opened the secret chamber knew of its existence," Gilbert went on, thinking the matter out aloud.
"Undoubtedly. He knew of its existence, and he also had the means of opening it."
Gilbert suddenly started, for an extraordinary notion had come into his mind. His father saw the start, and thought he knew its meaning. The two men looked at each other strangely.
"Only two men in the world, I feel certain, knew of that chamber," Eversleigh resumed. "One was the mechanic who devised and made it, the other was——"
"Cooper Silwood!" exclaimed Gilbert.
"Yes, Cooper Silwood."
"But Silwood is dead, so you would say that it was the other? That seems absurd."
"It is absurd. What would the mechanic who made the box care about taking anything out of the secret chamber? Once his job of making the thing was finished, he would be finished with it altogether. No, it was not the mechanic."
Gilbert was silent.
"Don't you see?" asked Eversleigh.